1. Field
The presently disclosed subject matter relates to an LED optical unit using an LED light source and vehicle lamps including the LED optical unit, and more particularly to vehicle lamps including a reliable LED optical unit having a connector which is mounted on a printed circuit board to receive a power supply from an external battery.
2. Description of the Related Art
Recently, various vehicle lamps using an LED light source have been developed. In the vehicle lamps, the LED light source and peripheral components are frequently assembled as an LED optical unit, which is attached to a predetermined position of a housing along with other components to form a single component in order to improve workability and provide other benefits.
In a manufacturing process for such an LED optical unit, an LED and printed circuit components that compose an LED driving circuit are soldered on a printed circuit board, for example, in a reflow process. After that, a connector for providing the printed circuit board with a power supply from an external battery is attached to the printed circuit board. In addition, a heat sink is frequently attached to a rear side of the printed circuit board via screws to reduce a junction temperature of the LED.
FIG. 12a is a front view showing a conventional attachment structure of a connector mounted on a printed circuit board, and FIGS. 12b and 12c are perspective views showing a connecting state of the connector and the coupler and a disconnecting state thereof, respectively. As shown in FIG. 12a, the connector 102 is attached to the printed circuit board 100 via screws 104. Terminals 102A, 102B and 102C of the connector 102 are electrically connected to conductor patterns of the printed circuit board 100 via a solder as shown in FIG. 12b. In this case, a coupler 106 is attachable to the connector 102 that is mounted on the printed circuit board 100 as shown in FIG. 12c. 
Another conventional attachment structure for a connector is shown in FIG. 13 and is configured as an attachment structure for a connector mounted on a printed circuit board that is disclosed in patent document No. 1 (Japanese Patent Application Laid Open JP2002-93500). The conventional connector 90a includes an insulating housing 93, which includes contact plates 97 and 98 and hooks 99. The insulating housing 93 is attached to a printed circuit board 94 by the hooks 99 so that the printed circuit board 94 is sandwiched between the insulating housing 93 and the hooks 99.
In this case, while each of contact points 97b and 98b of the contact plates 97 and 98 contacts conductor patterns 95 and 96 on the printed circuit board 94, the contact plates 97 and 98 extend between the insulating housing 93 and the printed circuit board 94 and create elastic forces such that the connector 90a separates from the printed circuit board 94. Accordingly, the connector 90a can be attached to the printed circuit board 94 without screws and/or solder.
For example, when a card 90b having electrodes 91 and 92 is inserted between the contact plates 97 and 98 of the connector 90a, each of the electrodes 91 and 92 of the card 90b can be electrically connected to the conductive patterns 95 and 96 of the printed circuit board 94 via conductor portions 97a and 98a of the contact plate 97 and 98 of the connector 90a. 
The above-referenced Patent Document is listed below and is hereby incorporated with its English abstract in its entirety.
1. Patent document No. 1: Japanese Patent Application Laid Open JP2002-93500
By using the above-described conventional attachment structure used in the connector 90a in an LED optical unit, the connector 90a may be attached to a printed circuit board without screws and/or solder. However, when the LED optical unit is used for a vehicle lamp, the LED optical may be subject to large vibrational forces. Accordingly, the contact points 97b and 98b are often attached to the conductor patterns 95 and 96 via solder, and thereby may be electrically connected to the conductor patterns 95 and 96 with confidence.
However, a crack may be caused in the solder portions because the connector 90a is also often used under high temperature conditions due to heat generated from LEDs. Therefore, as shown in FIG. 12a, a connector 102 can be attached to a printed circuit board 100 via screws 104. However, the conventional attachment structure shown in FIG. 12a may result in added cost because it increases the number of parts and the number of assembly processes.
After the terminals 102A-102C of the connector 102 are soldered along with the other components in a reflow process, and when the connector 102 is attached to the printed circuit board 100 via screws 104, a crack may be caused in the soldering portions due to the screwing force during assembly. Consequently, after the connector 102 is attached to the printed circuit board 100 via the screws 104, the terminals 102A-102C of the connector 102 may be soldered to the conductor patterns of the printed circuit board 100 by hand work. Therefore, the conventional attachment structure may result in a complex manufacturing process.
In contrast, by using the conventional attachment structure in which connector 90a shown in FIG. 13 is used in an LED optical unit, the soldering process and the screwing process for attaching the connector 90a to the printed circuit board 94 may be eliminated. However, the large vibration of a vehicle may cause a loose connection between the electrodes 91, 92 and the conductor portions 97a, 98a and/or between the conductor patterns 95, 96 and the conductor points 97b, 98b. Moreover, in a worst case scenario, the connector 90a may become totally removed from the printed circuit board 94 due to the large vibration and/or the card 90b may become totally removed from the connector 90a. 
The disclosed subject matter has been devised to consider the above and other problems, characteristics and features. Thus, an embodiment of the disclosed subject matter can include a vehicle lamp including an LED optical unit having a reliable connector that can be easily fixed and may not require the use of a screw and/or solder, and can be used in large vibration and shock conditions. In this case, the vehicle lamp can be constructed from only one optical unit that can be formed in a thin shape. Thus, the vehicle lamp can result in an increase in the possible range of vehicle lamp design options, and therefore can be employed for various vehicles including a small size car and a large size truck.